Transom/hull step for speed????

[Smoking Joe]

Can you guys please explain to me why some of the more modern hulls have a step at the rear of the planing surface and the transom?
At what sort of speed would this type of modification start to have an effect?
Does this mod on the Liberator effectively reduce the need for setback?
I have also seen this mod on V hulls.
I hope Randy doesn't mind me using a couple of photo's of his boat.



Attachment 240552

[Greg G]

Guys have done it and there are a variety of opinions. What hull are you thinking of doing this to?

[Smoking Joe]

Guys have done it and there are a variety of opinions. What hull are you thinking of doing this to?

Hey Greg, thanks for the photo. I am about to remove the sterndrive from a Wellcraft Nova 230 XL, reconfigure the transom and bracket a Johnson 300hp V8 on it. Since I will be doing plenty of transom work any mods that can be done at the same time to add speed will be worth doing.

I have a hydraulic Jack Plate for the engine. Would really like to see late 60'smph but I appreciate that this may be unrealistic with 300hp. I may also look to go with a Monty's power head which would give me another 70hp or so.

[VELOCITOY]

..What a great question..!..Would like to know the story on the step.!.Some discussion of pads would be tolerated too.. My thoughts on SJ's (Hi Wellcraft and what you're doing with the bracket & V8 makes the step a moot point. A pad would be a "maybe", ONLY if you want to change what is a great design to begin with..discuss away...

PS..been watch your journey..you da man.. SJ.. your mate from the granite state..Vtoy..

[rev.ronnie]

This is interesting. I think it applies more to high mph racing but good info nonetheless.
http://www.velocityboats.com/Safety.html

[Smoking Joe]

..What a great question..!..Would like to know the story on the step.!.Some discussion of pads would be tolerated too.. My thoughts on SJ's (Hi Wellcraft and what you're doing with the bracket & V8 makes the step a moot point. A pad would be a "maybe", ONLY if you want to change what is a great design to begin with..discuss away...

PS..been watch your journey..you da man.. SJ.. your mate from the granite state..Vtoy..

Hey Vtoy hows it going dude. I sure appreciate the pedigree of the Wellcraft hull, I had thought of putting a pad on it too. Now I am thinking that I will flag that idea. If the 300hp V8 is not fast enough and I like the V8 then I will buy another and get it to NZ via Monty. Another alternative is to put two 225hp's or go to Merc 300XS or maybe even 350 Verado.

When I rebuild the transom I will make it strong enough to handle twins.

PS..been watch your journey..you da man.. SJ.. your mate from the granite state..Vtoy..

"you da man..." With the difficulties I have faced with this "journey" you should have heard what my wife had to say about this "trip". Something along the lines of "you da stupid man, what is wrong with the thousands of boats for sale in New Zealand". These women just don't understand us mere males.

Take care mate.

Nev.

[Smoking Joe]

This is interesting. I think it applies more to high mph racing but good info nonetheless.
http://www.velocityboats.com/Safety.html

Thanks R.R, good link, makes for interesting reading.

[rev.ronnie]

From what I understand, a stepped transom gives the prop cleaner, more undisturbed water to run in, making it more efficient. Hydrostream did it very early on and till the end.

[bigboy]

I think it acts like setback. I believe they call this built-in setback.

That way you already have more setback without running a jackplate or setback plate.

So the benefit is the same as the setback => increase bowlift....

Correct me if I'm wrong.

[Smoking Joe]

So does it only work with a V hull sporting a pad or does the same principles apply to a V hull without a pad???

[Greg G]

Here is an added pad that is going on one of my boats. Give me details on the 230XL, beam, deadrise, weight, do the strakes run right to the transom?

[Smoking Joe]

Here is an added pad that is going on one of my boats. Give me details on the 230XL, beam, deadrise, weight, do the strakes run right to the transom?

Thanks Greg. I would like to see some clearer photo's, looks like an interesting exercise. Unfortunately my container has been held up by some inclement weather (my boat is still on the ship and is yet to arrive) so I am unable to supply measurements. I am probably getting a bit ahead of myself but seeing the photo's of Randy's tunnel motivated me to ask the question.

Thanks for your input.

Nev.

[OFFSHORE GINGER]

Can you guys please explain to me why some of the more modern hulls have a step at the rear of the planing surface and the transom?
At what sort of speed would this type of modification start to have an effect?
Does this mod on the Liberator effectively reduce the need for setback?
I have also seen this mod on V hulls.
I hope Randy doesn't mind me using a couple of photo's of his boat.



Attachment 240552

Joe , more lift......which means less wetted surface , which means more speed .................

[OFFSHORE GINGER]

Hey Greg, thanks for the photo. I am about to remove the sterndrive from a Wellcraft Nova 230 XL, reconfigure the transom and bracket a Johnson 300hp V8 on it. Since I will be doing plenty of transom work any mods that can be done at the same time to add speed will be worth doing.

I have a hydraulic Jack Plate for the engine. Would really like to see late 60'smph but I appreciate that this may be unrealistic with 300hp. I may also look to go with a Monty's power head which would give me another 70hp or so.

Joe , first off...... what year is the boat , and to tell you the truth ,Nova's are pretty much slugs on the water ,considering .......................they all seem to have rotted Stringer systems , Transoms , Bulkheads , Ext , Ext , Ext , ansd the list goes on .

[Smoking Joe]

Joe , first off...... what year is the boat , and to tell you the truth ,Nova's are pretty much slugs on the water ,considering .......................they all seem to have rotted Stringer systems , Transoms , Bulkheads , Ext , Ext , Ext , ansd the list goes on .

Hmmm, do I take it you are not a fan of the Wellcraft Nova then.........Mine is a 1985 Wellcraft Nova 230 XL.

Joe , more lift......which means less wetted surface , which means more speed .................

Yup that broad principle I understand. But specifically how does the transom step help with lift and speed????